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ENV 20067.2 Interaction Major difference between paper and computer-based visualization is ability to interact with picture and alter the presentation of the data Nice simple example is Dancing with Histograms –Dix and Ellis http://www.comp.lancs.ac.uk/computing/users/dixa/papers/simple98/ http://www.comp.lancs.ac.uk/computing/users/dixa/papers/simple98/ This lecture looks at two concepts: –Focus and context –Brushing

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ENV 20067.3 Focus and Context A recurring problem in Information Visualization is lack of screen real estate Challenge has been addressed in some innovative ways Want to achieve: –Focus: to see detail of immediate interest –Context: to see the overall picture Want to do this interactively… Six approaches: –Distortion –Rapid zooming –Elision –Multiple windows –Use 3D (more space) –Use animation (more time)

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ENV 20067.5 Bifocal Display Implemented as an image browser that scales different areas of image in different ways –Chris North, Univ of Maryland Available at: http://people.cs.vt.edu/~north/infoviz/

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ENV 20067.6 Bifocal Display A possible application is in map reading This London underground application was developed by Marcelo Cohen in Leeds Zoom / pan Focus /context

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ENV 20067.20 Elision Techniques Hide parts of a structure until they are needed Widely used in graph drawing software for very large graphs Have you seen this in xmdvtool?

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ENV 20067.21 Multiple Views Multiple views can also be used to provide focus and context Powerpoint uses this to good effect!

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ENV 20067.22 Move into 3D: Cone Trees Using a third dimension allows us to prioritise the focus (foreground) without losing the context (background) For large tree structures it is impossible to find sufficient screen space Cone trees in 3D provide a solution Here is a moviemovie http://research.compaq.com/SRC/3Danimate/conetree.html

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ENV 20067.23 Adding a time dimension: RSVP We can gain more space by adding time! Recent Spence work addresses problem of browsing information spaces –Rapid Serial Visual Processing –To gain a quick view of what is available –Distinction between browsing and searching –Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)movie

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ENV 20067.24 Browsing the Web Spence has also turned his attention to browsing the web –On mobile devices! –Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)movie

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ENV 20067.26 Linking: Coordinated Views Selection from one view can be linked to a corresponding selection in another view –Coordinated multiple views

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ENV 20067.27 Linking: Multiple Views Many of the concepts we have talked about are brought together in the Snap-Together system of Shneiderman and North How many visualizations can you recognise here? http://www.cs.umd.edu/hcil/snap/

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ENV 20067.29 Linking: Spence Attribute Explorer Spence has also developed a tool called Attribute Explorer –Compare it with xmdvtool –Look for brushing concept –Here is the movie (http://www.iis.ee.ic.ac.uk/~r.spence/videos.htm)movie